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The research carried out concerned the laboratory assessment of the applicability of the Crop Water Stress Index (CWSI) as a practical tool for assessing the risk of desiccation for selected wetland habitats: transition mires and quaking bogs as well as alkaline fens. The analysis was carried out on 3 soil samples with a vegetation cover (with the dimensions of 40×40×30 cm) collected during the full vegetation season for each mentioned habitat, with a characteristic species composition. Experimental research was carried out between 17th May 2018 and 19th June 2018. Thermal, RGB and multispectral images, chlorophyll content, volumetric soil moisture, air temperature and relative humidity measurements were taken for each sample every two days. The obtained results clearly indicate the dependence between CWSI and plant condition parameters in the first phase of desiccation. At the same time, as a result of the observations taken, thresholds have been set, indicating different desiccation phases.

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The driving force behind adopting the idea of ​​sustainable development are producers and retailers. Unfortunately, when preparing their product range for consumers, many of them still only pay attention to the size of the customers’ earnings, how often they shop and how much they buy when shopping. In consumer segmentation, sustainable values ​​that consumers apply when making their purchasing decisions are rarely taken into account. The aim of this article is to show that values ​​such as environmental protection, the ethical behaviour of producers, fair trade or maximising the utility function of consumption are so important in the purchasing process in the coffee market that they can be used as segmentation variables. The Polish coffee market was selected to carry out segmentation taking into account the consumers' sustainable values. The main source of the article is the results of a standardized online survey conducted on a nationwide sample of 800 coffee consumers in July 2018. Multi-dimensional analyses such as extrapolative factor analysis (EFA) and cluster analysis (CA) were used to describe the obtained results. As a result, six segments of coffee consumers were identified and described: “responsible, aspiring to be connoisseurs”, “loyal coffee enthusiasts”, “pragmatic users”, “coffee laypersons”, “sophisticated connoisseurs”, “consumerists, connoisseurs, but not at any price”. Among the identified segments, the sustainable consumption values ​​most often mentioned refer to "responsible, aspiring to be connoisseurs", and the least often - ”consumerists, connoisseurs, but not at any price”. The conclusions presented in the last part of the article may be used by manufacturing and trade enterprises, operating on the coffee market, in order to respond to the identified needs and expectations of consumers and by governmental and social organisations so as to determine the directions of pro-ecological education of consumers.

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Droughts occurring more and more frequently in recent years are usually associated with progressive climate changes. Modern monitoring methods is mainly associated with agricultural use due to the high market demand for services protecting against agricultural losses. In natural wetland ecosystem this problem is neglected which is probably due to fact that this are ecosystems rich in water by definition. Nevertheless this droughts might become a problem of wetlands, whose good condition depends on adequate hydration. Therefore this study focused on determination Crop Water Stress Index (CWSI) for natural heterogeneous wetland habitats. CWSI based on remotely sensed land surface temperature and associated basic meteorological (air temperature and humidity) measurements. CWSI was calculated based on high resolution LST measurements from UAV platform and compare with on ground measurements of soil moisture, CCI, fAPAR and meteorological conditions. Results shows that CWSI properly shows water condition of plants in measured habitats and revels high importance of metrological conditions during data acquisition.

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The article addresses the issue of consumer preferences for types of coffee in Poland (ground coffee, instant coffee, coffee beans, instant coffee mixes and instant cappuccino). The main source of the study is the results of primary research conducted using a structured interview (CAPI—Computer Assisted Personal Interview) on a nationwide sample of 800 coffee consumers. The research was conducted by Grupa IQS Sp. z o.o. from Warsaw in January 2016 for the MOKATE Group based on the assumptions and guidelines developed by the authors of the article. The main purpose of the article is to present the identified coffee consumer preferences in Poland with regard to various kinds of coffee. The results of the research which have been included in the article indicate, among others, ongoing changes in the preferences of Polish consumers regarding their coffee choices. They prove that Polish consumers are drinking ground coffee more and more often. The consumption of instant coffee is decreasing.

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This article contains the theorems concerning the algebraic dependence of polynomial mappings with the constant Jacobian having two zeros at infinity. The work is related to the issues of the classical Jacobian Conjecture. This hypothesis affirm that the polynomial mapping of two complex variables with constant non-zero Jacobian is invertible. The Jacobian Conjecture is equivalent to the fact that polynomial mappings with constant non-zero Jacobian do not have two zeros at infinity, therefore it is equivalent to the two theorems given in the work. The proofs of these theorems proceeds by induction.

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The main aim of the study was to analyze/determine how international modern retailers’ chains can achieve a competitive advantage by introducing private labels (PLs) in the organic category and in turn stimulate consumption of food produced with respect of sustainability principles. Following a review of the relevant literature data collection process involved two steps. First, to select retailers with organic private labels (OPLs) and producers delivering products under OPLs, there were conducted in-depth semi-structured interviews with the representatives of the management board of 17 enterprises. A group of 6 enterprises was selected, including 3 retailers having OPLs, 2 producers delivering products under OPLs and one enterprise that was categorized as producer and distributor. Based on the results of the interviews, six sources of the competitive advantage of the OPLs were identified and further discussed. Second, to analyze more in depth assortment-based competitive advantage of the OPLs, 8 enterprises (5 retailers having OPLs, 2 producers delivering products under OPLs and one enterprise categorized as a producer and distributor) were approached for the interviews. To explore price-related competitive advantage three products offered under the premium PLs, the economy PLs, the organic PLs, the producer brands and the imported brands were selected for the subsequent analysis. Increasing competition in the food retailing sector pose many challenges on the retailers and stimulate them to develop the PLs that is in line with global trends. In case of the OPLs, the more popular strategy while introducing them is to differentiate the PLs with quality and image related attributes comparable to leading producer brands. Retail chains introducing the OPLs achieve the competitive advantage related to six sources: price, range of assortment, type of PLs, image of retailer, sustainability and specific process and product related attributes of organic food. Additionally the retailers use their reputation and image of retailers’ brand to guarantee the quality of new organic products introduced under the PLs. To achieve or maintain the competitive advantage, retailers tend to introduce the OPLs positioned as value added PLs. They perceive the OPLs as a way to influence the consumers' decision to buy and increase their loyalty towards store brands. The strategies of the retailers evolve and the largest retailers decided to create the premium OPLs, the others focus on introduction of the international OPLs or aim at development of new PLs based on the analysis of consumers' preferences. There are several factors behind the decision to introduce or extend the premium OPLs i.e. to expand the assortment of organic products and green products line, to increase category margins and to enhance retailer’s image among customers. Other large retailers create the OPLs with special product line design focusing on health- and environmental related attributes and high quality guaranteed by the organic regulations and the certification. The process of the introducing the premium PLs should be influenced by the inherent characteristic of organic food and its production methods that respect the principles of the sustainable development.

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Drought periods have an adverse impact on the condition of oak stands. Research on different types of ecosystems has confirmed a correlation between plant species diversity and the adverse effects of droughts. The purpose of this study was to investigate the changes which occurred in an oak stand (Krotoszyn Plateau, Poland) under the impact of the summer drought in 2015. We used a method based on remote sensing indices from satellite images in order to detect changes in the vegetation in 2014 and 2015. A positive difference was interpreted as an improvement, whereas a negative one was treated as a deterioration of the stand condition. The Shannon-Wiener species diversity was estimated using an iterative PCA algorithm based on aerial images. We observed a relationship between the species indices of the individual forest divisions and their response to drought. The highest correlation between the index differences and the Shannon-Wiener indices was found for the GNDVI index (+0.74). In addition, correlations were observed between the mean index difference and the percentage shares in the forest divisions of species such as Pinus sylvestris (+0.67 ± 0.08) and Quercus robur (-0.65 ± 0.10). Our results lead us to infer that forest management based on highly diverse habitats is more suitable to meet the challenges in the context of global climatic changes, characterized by increasingly frequent droughts.

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This study estimates rainfall interception losses from natural wetland ecosystems based on maximum canopy storage measurements. Rainfall interception losses play an important role in water balance, which is crucial in wetlands, and has not yet been thoroughly studied in relation to this type of ecosystem. Maximum canopy storage was measured using the weight method. Based on these measurements, daily values of interception losses were estimated and then used to calculate long term interception losses based on precipitation and potential evapotranspiration data for the 1971–2015 period. Depending mainly on the number of days with precipitation, the results show that total interception losses for the growing season as well as monthly interception losses are around 13% of gross rainfall. This value is similar to the values observed for some forests. Hence, interception losses should not be disregarded in hydrologic models of wetlands, especially because data trends in meteorological conditions (mainly number of days with precipitation) show that interception losses will increase in the future if those trends stay the same.

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